feat: day 5 solution

README.md

@@ -11,12 +11,13 @@ Solutions for [Advent of Code](https://adventofcode.com/) in [Rust](https://www.
 
 | Day | Part 1 | Part 2 |
 | :---: | :---: | :---:  |
-| [Day 1](./src/bin/01.rs) | `46.9µs` | `115.3µs` |
-| [Day 2](./src/bin/02.rs) | `75.9µs` | `124.8µs` |
-| [Day 3](./src/bin/03.rs) | `69.4µs` | `90.7µs` |
-| [Day 4](./src/bin/04.rs) | `2.7ms` | `54.1µs` |
+| [Day 1](./src/bin/01.rs) | `45.6µs` | `89.9µs` |
+| [Day 2](./src/bin/02.rs) | `124.5µs` | `219.8µs` |
+| [Day 3](./src/bin/03.rs) | `79.5µs` | `80.1µs` |
+| [Day 4](./src/bin/04.rs) | `3.9ms` | `62.1µs` |
+| [Day 5](./src/bin/05.rs) | `398.2µs` | `501.8µs` |
 
-**Total: 3.28ms**
+**Total: 5.50ms**
 <!--- benchmarking table --->
 
 ---

data/examples/05.txt

@@ -0,0 +1,28 @@
+47|53
+97|13
+97|61
+97|47
+75|29
+61|13
+75|53
+29|13
+97|29
+53|29
+61|53
+97|53
+61|29
+47|13
+75|47
+97|75
+47|61
+75|61
+47|29
+75|13
+53|13
+
+75,47,61,53,29
+97,61,53,29,13
+75,29,13
+75,97,47,61,53
+61,13,29
+97,13,75,29,47

src/bin/05.rs

@@ -0,0 +1,110 @@
+use std::{
+    cmp::Ordering,
+    collections::{HashMap, HashSet},
+};
+
+advent_of_code::solution!(5);
+
+pub fn part_one(input: &str) -> Option<u32> {
+    let mut sum = 0;
+    let (orders, updates) = read_protocols(input);
+    for update in updates {
+        let mut valid = true;
+        for i in 0..update.len() - 1 {
+            for j in i + 1..update.len() {
+                if let Some(values) = orders.get(&update[i]) {
+                    if !values.contains(&update[j]) {
+                        valid = false;
+                    }
+                } else {
+                    valid = false;
+                    break;
+                }
+            }
+        }
+        if valid {
+            sum += update[update.len() / 2];
+        }
+    }
+    Some(sum)
+}
+
+pub fn part_two(input: &str) -> Option<u32> {
+    let mut sum = 0;
+    let (orders, updates) = read_protocols(input);
+    for update in updates {
+        let mut valid = true;
+        for i in 0..update.len() - 1 {
+            for j in i + 1..update.len() {
+                if let Some(values) = orders.get(&update[i]) {
+                    if !values.contains(&update[j]) {
+                        valid = false;
+                    }
+                } else {
+                    valid = false;
+                    break;
+                }
+            }
+        }
+        if !valid {
+            sum += reorder(&orders, &update);
+        }
+    }
+    Some(sum)
+}
+
+fn read_protocols(content: &str) -> (HashMap<u32, HashSet<u32>>, Vec<Vec<u32>>) {
+    let (input_order, input_updates) = content.split_once("\n\n").unwrap();
+    (
+        input_order.lines().fold(HashMap::new(), |mut map, order| {
+            let (first, second) = order.trim().split_once('|').unwrap();
+            map.entry(first.parse().unwrap())
+                .or_default()
+                .insert(second.parse().unwrap());
+            map
+        }),
+        input_updates
+            .lines()
+            .map(|update| {
+                update
+                    .trim()
+                    .split(',')
+                    .map(|num| num.parse().unwrap())
+                    .collect()
+            })
+            .collect(),
+    )
+}
+
+fn reorder(orders: &HashMap<u32, HashSet<u32>>, update: &[u32]) -> u32 {
+    let mut sorted = update.to_owned();
+    sorted.sort_by(|a, b| {
+        if let Some(b_vals) = orders.get(b) {
+            if b_vals.contains(a) {
+                Ordering::Greater
+            } else {
+                Ordering::Less
+            }
+        } else {
+            Ordering::Less
+        }
+    });
+    sorted[update.len() / 2]
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_part_one() {
+        let result = part_one(&advent_of_code::template::read_file("examples", DAY));
+        assert_eq!(result, Some(143));
+    }
+
+    #[test]
+    fn test_part_two() {
+        let result = part_two(&advent_of_code::template::read_file("examples", DAY));
+        assert_eq!(result, Some(123));
+    }
+}